The existing microsphere tracers are mainly prepared by taking polystyrene as raw material and have the disadvantages of poor biocompatibility and poor in vivo degradability. The specific methods thereof are divided into the following two methods. A method includes embedding radioactive nuclides and the compounds thereof in microspheres to prepare radioactive microspheres. After the radioactive microspheres enter the body, a nuclear detector is used to trace the radioactive microspheres for the different positions, contents and conversions thereof in vivo. This method is complex in operation, great dangerous, and demands high experimental conditions, and additionally, it is unsuitable for oral tracing and intracellular tracing1-3. The other method includes embedding fluorescent substances in microspheres to prepare fluorescent microspheres. After the fluorescent microspheres enter the body, a fluorescence microscope is used to observe the distribution situation of the fluorescent microspheres in vivo. However, many fluorescent dyes are not stable sufficiently and will quench gradually in vivo. Additionally, the fluorescent substances adhered on the surface of the microspheres will result in the change of the charges on the surface of the microspheres so as to affect the distribution trends thereof, and therefore, the complexity of the research is increased. Furthermore, the fluorescent substances all have certain toxicity which limits the uses of this kind of tracers4.